When integrated circuit chips are cycled (e.g., during burn-in) they require instantaneous currents at their power pins. These high speed current transients induce instantaneous voltage drops in the power distribution lines leading to the integrated circuit chip. If these voltage drops exceed a couple of volts, the chip performs unpredictably. As a result, it is desirable to be able to hold these instantaneous voltage drops to a minimum.
Previously, the cables used for supplying power to integrated circuit chips have been a major contributor to voltage drops due to the inherent inductance of such cables.
Another situation in which the inductance of conventional cables is detrimental is in burn-in of integrated circuit chips. Burn-in is often performed on integrated circuit chips after manufacture and before they are shipped from the foundry. Burn-in is used to reduce infant mortality failures which can result from manufacturing process anomalies.
On conventional surface mount parts the burn-in process includes the following steps: (1) electrical testing to verify that the part is good prior to burn-in; (2) loading the parts onto burn-in boards; (3) loading the burn-in boards into the burn-in oven one at a time; (4) verifying the burn-in signals on the burn-in boards; (5) dynamically cycling the parts for an extended period in the burn-in oven; (6) verifying the burn-in signals on the burn-in boards before the parts are removed from the oven to ensure that the board received the test vectors during the entire burn-in period; (7) unloading the parts from the burn-in boards; and (8) electrical testing of burned-in parts.
Current burn-in methods require the purchase, design and debug of burn-in and timing boards. More recent burn-in systems require the programming of PROMs to create the burn-in test vectors. The burn-in boards are typically socketed for individual parts. The sockets require the part to have fairly large leads to handle the large temperature excursion experienced during the burn-in oven on/off cycles. The cost of these sockets increases as the lead pitch becomes smaller.
The part packing density in the burn-in oven is fairly low, typically requiring eight cubic inches per part. This results in larger oven capacity requirements and 24 hour maximum burn-in times.
There has not heretofore been provided a high capacitance cable having the advantages provided by the present invention.